The 40-year-old mother of two credits a five-day-a-week exercise regimen for keeping her in shape as she grows older.

“It makes me look younger and feel strong,” Paltrow told the magazine. “When I first started, I thought, ‘I’ll never be good at this. This is a nightmare!’ But now it’s like brushing my teeth, I just do it.”

It is the fourth time Paltrow, who is married to Coldplay singer Chris Martin, has been named to the magazine’s annual beautiful people issue, but the first time landing the coveted cover as most beautiful woman.

She joins the likes of fellow actresses Jennifer Lopez, Julia Roberts, Halle Berry and Jennifer Aniston to top the list.

Paltrow reprises her starring role as Pepper Potts in the action film “Iron Man 3,” which opens next month.

The actress has cut back her film work after giving birth to children Apple, 8, and Moses, 7, and released her second cookbook, “It’s All Good,” this month.

She is also the founder of lifestyle and clothing website Goop.com.

Paltrow won an Oscar for her role as William Shakespeare’s muse in the 1998 film “Shakespeare in Love.”

The full list of People’s “World’s Most Beautiful People” can be found on www.people.com/mostbeautiful